VPN or Virtual Private Network provides secure and reliable private connection between computer networks over an existing public network mostly internet.VPN enables employees to securely access their company’s network; it can easily connect the various branches of an office using a cohesive network. Though it sends and receives data across shared and public networks, it provides the security while managing private network. VPN is easily substituting leased lines for their lower costs than the earlier mode of leased lines. It is also better than leased lines in its functions and efficiency. VPN service is proving to be more effective and achieving better goals including the maintenance of privacy. VPN allows only authenticated remote access using encryption techniques to prevent the disclosure of private information. All the data send from one computer is encrypted in a method that only the computer that it is being sent to can decrypt it.VPN is known for its security mechanisms that provide confidentiality that ensures that only encrypted data is visible to any unauthenticated user trying to interfere with the network. Moreover, sender authentication prevents unauthorized users from accessing the VPN. VPNs can be either connecting two networks or be remote access for connecting a computer to a network. The remote access VPN enables individual users to establish secure connections with a remote computer network. Users can access on the network simply as though they are directly connected to the network’s server. VPN is facilitating organisations to preserve their privacy while creating internal networks.